Multi-phase simulation environment

ABSTRACT

A Multi-Phase Simulation Environment (“MPSE”) is provided which simulates the conductor current and voltage or electric field of multiple phases of an electrical power distribution network to one or more sensing or measuring devices and includes independent control of wireless network connectivity for each sensing or measuring device, independent control of GPS RF to each device, and interface to a back-end analytics and management system.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/714,541, filed Dec. 13, 2019, titled “Multi-Phase SimulationEnvironment, and which claims the benefit of U.S. Provisional PatentApplication No. 62/779,305, filed Dec. 13, 2018, and titled “Multi-PhaseSimulation Environment.” The contents of each of the aforementionedapplications are incorporated by reference herein.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference.

FIELD

The present application relates generally to distribution linemonitoring, sensor monitoring, and sensing and identifying electricalcharacteristics of a power distribution line. More specifically, thepresent disclosure relates to testing devices for simulating electricalcharacteristics of an electrical grid to test line sensing devices forquality control or new features.

BACKGROUND

In providing power to customers, electrical power utility companiesemploy a power grid distribution network that includesdistribution-line-conductors (which are often referred to as powerlines). Typically, difficulties or faults within the distributionnetwork are identified only after occurrences of “events.” These eventsmay merely result in a temporary loss of power for a limited number ofcustomers, but more significant problems may occur.

Protection components and systems are known. “Reactive” components areparticularly common. A reactive component is a device or system that isactivated or deactivated by a fault event or its consequences. Forexample, a circuit breaker will open a transmission line as a responseto excessive current, thereby protecting power distribution equipment.More sophisticated systems are also available.

Clearly, there are benefits to identifying conditions that precede faultevents. For example, if it can be determined that a power line from apower transformer is experiencing intermittent fluctuations, schedulinga replacement of the transformer to avoid an outage event would bebeneficial to the utility provider and its customers. Thus, “predictive”components and systems are desirable. Monitoring systems that monitorpower parameters of equipment and power lines can provide usefulinformation for the prevention and identification of power distributionfaults or events.

Line monitoring devices typically take the form of a sensor monitoringthe electric current and electric field (“E-field”) or voltage of aconductor in the utility network, and provide output data consisting ofmeasurements and analysis of the conductor via wireless network (meshWLAN, cellular WWAN, or “WAN”). In addition to providing location data,the use of GPS by these sensors provides a precise timing referencewhich enables coordination of measurement activity across a widelydeployed population of sensors which otherwise share no common directconnection. The output data from each sensor is typically returned to a“back-end” management system, which stores the data for furtheranalysis, management display, etc.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe claims that follow. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIG. 1 is a schematic diagram of a MPSE system.

FIG. 2 is a schematic diagram illustrating waveform generation in theMPSE system described herein.

FIGS. 3A-3D are diagrams illustrating waveform generation with amaster-slave waveform generator approach.

FIGS. 4A-4B are diagrams showing a way of coordinating the waveforms inthe system.

FIG. 5 is a flowchart describing a method for simulating and measuringelectrical characteristics of a power grid network.

SUMMARY OF THE DISCLOSURE

A method for simulating and measuring electrical characteristics of apower grid network is provided, comprising the steps of generating async waveform from a master waveform generator to one or more slavewaveform generators to provide a phase locked loop reference between themaster waveform generator and the one or more slave waveform generators,generating a trigger signal from the master waveform generator to theone or more slave waveform generators to initiate a first event waveformof a waveform playlist, delivering the first event waveform of thewaveform playlist from the master waveform generator and the one or moreslave waveform generators to one or more devices under test, measuringelectrical characteristics of the first event waveform with the one ormore devices under test, generating a trigger signal from the masterwaveform generator to the one or more slave waveform generators toinitiate a subsequent event waveform of the waveform playlist,delivering the subsequent event waveform of the waveform playlist fromthe master waveform generator and the one or more slave waveformgenerators to the one or more devices under test, and measuringelectrical characteristics of the subsequent event waveform with the oneor more devices under test.

In some examples, the method further comprises measuring electricalcharacteristics of the first event waveform and the subsequent eventwaveform with an oscilloscope. The method can further comprise comparingthe electrical characteristics measured by the oscilloscope to theelectrical characteristics measured by the one or more devices undertest.

In some embodiments, the first event waveform comprises a simulatedcurrent signal and a simulated voltage signal. In one embodiment, themeasured electrical characteristics of the first event waveform comprisea simulated conductor current and an electric field signal.

In some embodiments, the sync waveform comprises a square wave sharedamong the master and slave waveform generators.

In some examples, the one or more devices under test comprise one ormore power line monitoring sensors.

In one embodiment, the first event waveform comprises a backgroundwaveform that represents typical waveform characteristics of a normallyoperating power grid. In another embodiment, the subsequent eventwaveform comprises an event waveform that represents a fault,disturbance, or power outage of a power grid.

In some examples, the first event waveform is delivered from the masterwaveform generator and the one or more slave waveform generators in thephase locked loop reference.

A power grid simulation system is also provided, comprising a firstdevice under test configured to measure electrical characteristics on afirst conductor, a second device under test configured to measureelectrical characteristics on a second conductor, a master waveformgenerator electrically coupled to the first device under test, themaster waveform generator being configured to apply a first simulatedcurrent and a first simulated voltage on the first conductor to thefirst device under test, a slave waveform generator electrically coupledto the second device under test, the master waveform generator beingconfigured to apply a second simulated current and a second simulatedvoltage on the second conductor to the second device under test, whereinthe master waveform generator is configured to generate a trigger signalfrom to the slave waveform generator to initiate a first event waveformand a subsequent event waveform of a waveform playlist, and wherein themaster waveform generator and the slave waveform generator areconfigured to deliver the first event waveform and the subsequent eventwaveform of the waveform playlist to the first and second devices undertest in a phase locked loop.

The system can further include an oscilloscope configured to measureelectrical characteristics of the first event waveform and thesubsequent event waveform.

In some examples, the system further comprises a central processing unitconfigured to compare the electrical characteristics measured by theoscilloscope to the electrical characteristics measured by the first andsecond devices under test.

In one embodiment, the first event waveform comprises a simulatedcurrent signal and a simulated voltage signal.

In some examples, the measured electrical characteristics of the firstevent waveform and the subsequent event waveform comprise a simulatedconductor current and an electric field signal.

In one embodiment, the master waveform generator is further configuredto provide a sync waveform to keep the master waveform generator and theslave waveform generator in the phase locked loop.

In some embodiments, the first and second devices under test comprisepower line monitoring sensors.

In one example, the first event waveform comprises a background waveformthat represents typical waveform characteristics of a normally operatingpower grid.

In another embodiment, the subsequent event waveform comprises an eventwaveform that represents a fault, disturbance, or power outage of apower grid.

DETAILED DESCRIPTION

The present disclosure provides line monitoring sensors and testingsystems that simulate the conductor current and voltage or electricfield of multiple phases of an electrical power distribution network,provide independent control of wireless network connectivity for eachsensing or measuring device, provide independent control of GPS RF toeach device, and interface to a back-end analytics and managementsystem. The present disclosure provides systems and methods whichsimulate the conductor current and voltage or electric field of multiplephases of an electrical power distribution network to one or moresensing or measuring devices for testing and quality control.

Described herein, and shown in FIG. 1, is a multi-phase simulationenvironment (“MPSE”) 100 which provides a simulated testing environmentfor one or more line monitoring devices or sensors (thedevices-under-test, or “DUTs”) 102 a, 102 b, and 102 c, each havingtheir own power supply. Although three DUTs on three simulatedconductors are shown in FIG. 1, it should be understood that the numberof simulated conductors and devices-under-test may be scaled uparbitrarily.

The MPSE as disclosed herein includes waveform generator(s) 104 a, 104b, and 104 c electrically coupled to each DUT to provide a simulatedcurrent and simulated voltage to each corresponding DUT. The waveformgenerators further provide trigger and sync waveforms between thewaveform generators which enables independent 360° control of the phaseangle of each simulated conductor within a single common angular frameof reference, so that the real-time phase relationships between allsimulated conductors may be controlled and maintained. This enablesrunning test scenarios which would not be possible if the phaserelationships between multiple individual conductors could not becontrolled and maintained. In one example, the sync waveform can be a 10mhz square wave that is shared among the waveform generators. The syncwaveform provides a common phase locked loop reference.

The present disclosure provides systems and methods by which an array ofline monitoring devices or sensors (the devices under test, or DUT) andthe back-end analytics and management system (themanagement-system-under-test, or “MSUT”) 106 may be exercised in thiscontext. A MPSE control unit 108 can be configured to setup and controlthe operation of the MPSE itself.

The MPSE provided herein also enables independent control of all otherparameters of each simulated utility conductor, while maintaining acoordinated and coherent frame of reference over the simulated network.Furthermore, the individual control over each parameter for eachsimulated conductor translates to the ability to perform testing andanalysis over the full range of possible scenarios, as opposed toexisting test equipment which are typically limited to prescribed orstandardized fault scenarios, phase values, current and voltage ranges,etc. This makes the MPSE particularly valuable in developing novelmeasurement and analytic techniques both at the level of the individualsensor, including hardware as well as embedded software, and in therealm of the back-end analytics and management system, in particularwhere these techniques rely on some form of coordination across thesensor population.

The MPSE provides functionality which may not be possible with othertest equipment, including off-the-shelf purpose-designed tools. In caseswhere there is functional overlap with existing tools, the combined costof MPSE components may be significantly lower. In particular, theability to simulate a scalable number of grid conductors within acoordinated frame of reference, including configuration and control overboth phase relationships and the simulation and timing of events such asfaults, load changes, disturbances, or other events, is unique.

Additionally, the MPSE can include a WAN control that controls theavailability of WAN RF to each DUT. The WAN control may includeprogrammatic control of RF switches or programmable attenuators. The WANcontrol may also control the network interface status of the MSUT and/orother network components.

The MPSE of the present disclosure can further include a GPSdistribution interface to coordinate the DUTs. The GPS signal can bereceived by an active antenna, which may be some distance away in orderto obtain clear view of the sky. The GPS signal can then distributed toeach DUT individually via power dividers (and amplifiers if necessary).The GPS signal path may include RF switches or manual or programmableattenuators to enable reducing or removing GPS signal as part of testscenario.

The DUTs, or monitoring devices, are configured to be mounted to powerlines or primary conductors of a power distribution network, such as athree phase AC network. The monitoring device can be configured tomonitor, among other things, current flow in the simulated lines andvoltage/current waveforms, conductor temperatures, ambient temperatures,vibration, and monitoring device system diagnostics. The monitoringdevice can further include wireless and or wired transmission (WLAN) andreceiving capabilities for communication with a central server and forcommunications between other monitoring devices. The monitoring devicecan be configured to also measure the electric field surrounding thesimulated lines, to record and analyze event/fault signatures, and toclassify event waveforms. Current, voltage, and electric field waveformsignatures can be monitored and catalogued by the monitoring device tobuild a comprehensive database of events, causes, and remedial actions.

The DUTs further include a plurality of power supplies (e.g., one powersupply for each DUT/waveform generator). Programmable power suppliesenable scenarios which include reducing or shutting off power to the DUT(which enables testing of DUT power management functions). Power may besupplied directly, or as an input to DUT power-harvesting circuitry.This may include control of power to RF components or switches forWAN/GPS.

The DUTs of the MPSE may be electrically isolated from the rest of thesystem. For example, each DUT may be housed inside a RF-isolating metalenclosure. The enclosures can be lined with RF-absorbing material toreduce reflection. The enclosures may further provide individual controlof DUT WAN and GPS access, and prevent unwanted rebroadcast of GPSsignals. Signal pass-throughs can also be provided for conductor currentand E-field or voltage signals, WAN and GPS RF, USB, RS-232, and DCpower.

Existing test tools may offer the ability to simulate some of theseparameters, but the control range may be limited, and the total numberof simulated conductors is typically limited to between one and threeconductors for phase-related simulations including both current andvoltage. More than one of an existing tool may be used for largernumbers of simulated conductors, but scaling in this manner wouldrequire a very high expenditure. Also, control of the phase relationshipand/or sub-millisecond event timing between each of these devices maystill not be possible.

The MPSE can provide testing of features including automatic phaseidentification, fault localization (via “last sensor” determination),disturbance detection and classification, and phase imbalance. Whilesome aspects of these features and relevant system components can betested or exercised individually, the end-to-end testing of thesefeatures requires the full scalability and control offered by the MPSE.

Referring to FIG. 1, the MPSE controller can be controlled via the MPSEcontroller 108 to select test criteria and waveform definition viaeither automated configuration or manual input, coordinate configurationof test equipment and DUT before, during, and after test, coordinatecollection of data for post-test analysis, and include interface to testequipment, DUTs and MSUT.

Waveforms for the DUTs can be defined programmatically from storedparameters and generated by the waveform generators. A waveform sequencecan be defined for each simulated conductor comprising of one or morepairs of conductor current, E-field, or voltage waveforms. Waveforms maydirectly represent the simulated conductor, or may be calculated tosimulate, for example, Rogowski coil output corresponding to conductorcurrent. The number of waveforms and the length of each are typicallythe same for all simulated conductors, while the phase angle, magnitude,harmonic content, or other parameters can be varied according to thetest requirements. These waveforms can be generated as data files andare then scripted into a “playlist” of waveform events to be triggeredin turn. The waveform generators can be programmatically configured atruntime with the waveform and playlist files as well as other hardwareparameters.

FIG. 2 is a schematic diagram illustrating waveform generation in theMPSE system described herein. As shown, the system components involvedin waveform generation include, but are not limited to, one or more DUTs202, one or more waveform generators 204, and a hardware interface 210between the waveform generator(s) and the input of each DUT that caninclude, among other components, current/voltage amplifiers, baluns,and/or differential amplifiers. The hardware interface enables eachwaveform generator to drive a wide variety of hardware inputs notdirectly compatible with the generator (high current, high voltage,etc.). Several different forms of DUT interface are available, includinga current amplifier to drive a Rogowski coil or other current sensingdevice, a high-voltage amplifier to drive a capacitive E-field sensorinput, a balun or other impedance transformer to simulate potentialtransformer output, or a direct test input requiring simulated Rogowskicoil output or other “converted” current or voltage signal analog.

An oscilloscope 212 can be connected to the various outputs of thewaveform generator to accurately measure the signals produced. Theoscilloscope can be connected to each waveform generator output toprovide a way of recording the simulated conductor current and E-fieldsignals. Alternately, the oscilloscope may be connected at the input tothe DUT (downstream of the hardware interface 210).

In some embodiments, the waveform generators are interconnected in amaster-and-slave configuration, with a single master waveform generator204 and one or more slave waveform generators (not shown in FIG. 2). Thewaveform generators are configured to share: 1) a high-frequencysynchronization signal, which enables maintaining phase lock between thewaveform generators for extended periods, 2) a digital trigger signal,initiating each event in the “playlist” of waveforms. This can beprovided to the master in the form of a SCPI command and is subsequentlydistributed to the slaves as a TTL pulse, resulting in near simultaneouswaveform event transitions between waveform generators. Generation ofthe master trigger signal may include the GPS-derived pulse-per-secondsignal (or “PPS”) as a timing reference for control of the phaserelationship between PPS and the waveform generator output.

FIGS. 3A-3D illustrate waveform generation with the master-slaveapproach described above. Generally, waveform data is downloaded to thegenerators, and waveforms are constructed for each phase so thatrelationships between phases are built-in to the generators. FIGS. 3A-3Cillustrate waveforms for the simulated conductor current of Phase A,Phase B, and Phase C, respectively. FIG. 3D illustrates a schematicdiagram of the master-slave waveform generator relationship, representedby master waveform generator 304 a and slave waveform generators 304 band 304 c. In one example, a trigger signal is initiated to the masterdevice 304 a (such as by the MPSE controller described above), which isthen passed on to the slave devices 304 b and 304 c with the trigger outconnections between waveform generators. This maintains the timealignment of play-listed waveforms. A syncing function enablesphase-lock between waveform generators, which provides the ability tomaintain phase relationships over long (multi-day) periods if desired.

FIG. 4A is a diagram showing an example of coordinating the variousphases of the conductor current waveforms in the MPSE system. FIG. 4B isone example of a waveform “playlist” including one or more “background”and “event” waveforms that are triggered by the master waveformgenerator (via the trigger sync) to sync the waveforms among the variouswaveform generators. As shown in FIG. 4B, the waveforms are designed tobe part of a “playlist” sequence, which can include background and eventwaveforms. The waveforms represented along timescales 414 and 418 inFIG. 4B represent a “background” waveform, which can, for example,represent a typical waveform that a line monitoring device might measureon a power grid conductor during normal operation. The waveformrepresented along timescale 416, however, can represent an “event”waveform, which can, for example, represent a waveform that a linemonitoring device might measure when there is a fault, disturbance, orpower outage event on a power grid conductor. The playlist sequence mayalso contain elements of differing lengths. As shown, the firstbackground waveform along timescale 414 has a different duration thanthe event and background waveforms along timescales 416 and 418.Individual sequence elements must be the same length for all phases(e.g., Phase A, Phase B, and Phase C). Each event can be initiated via atrigger signal from the MPSE controller and/or master waveformgenerator, and coordination between the waveform generators can bemaintained by a combination of a shared trigger signal, an event length,a sample rate, and a phase lock.

Example Scenario

A typical scenario executed within the MPSE may proceed as follows, andas illustrated in flowchart 500 of FIG. 5: In this example, the testwill target the DUTs' ability to provide independent measurement ofconductor phase angle to the MSUT under a prescribed set of conditionsregarding the conductors and GPS availability. Data will also becollected to evaluate the output of subsequent MSUT analysis.

The example test configuration includes three simulated conductors withone DUT assigned to each conductor, with the DUTs connected to theback-end MSUT. In this scenario, all three DUTs will have normal power,WAN, and GPS available through the test. The conductor current andE-field will be maintained at normal levels with no added noise orharmonics. The phase angles of the three simulated conductors can bearranged at intervals of 120° as a normal three-phase triplet. For eachsimulated conductor, the corresponding conductor current and E-fieldwaveforms can share the same phase angle (zero reactive power).

The test begins by establishing configuration values and settings forthe necessary components of the system. Relevant data is collected fromthe DUTs and MSUT. DUT firmware can be uploaded if necessary, and theDUTs are configured to a quiescent state. At optional step 502 of theflowchart 500, waveform data can be generated as prescribed for thewaveform generators, including generating a waveform playlist with morethan one waveform event.

Next, the waveform generators apply the prescribed waveform playlist toprovide a simulated current and a simulated voltage to the DUTs. At step504, a master waveform generator can initialize a sync waveform to oneor more slave waveform generators to provide a common phase locked loopreference.

Next, at step 506, the method can further include generating a triggersignal from the master waveform generator to the one or more slavewaveform generators to initiate waveform playlist. At step 508, themethod can include delivering a first event waveform of the waveformplaylist from the master and slave waveform generators to one or moredevices under test. For example, the first event waveform of thewaveform playlist may be a background waveform (e.g., a waveform thatrepresents typical waveform characteristics of a normally operatingpower grid). At step 509, the method can include measuring the firstevent waveform with the one or more devices under test. Measuring canincluding measuring the electrical characteristics of the first eventwaveform, including but not limited to measuring current amplitude,phase angle, voltage amplitude, E-field, etc.

Next, at step 510, the method can further include generating a triggersignal from the master waveform generator to the one or more slavewaveform generators to initiate a subsequent event waveform from thewaveform playlist. At step 512, the method can include delivering asubsequent event waveform of the waveform playlist from the master andslave waveform generators to one or more devices under test. Forexample, the subsequent event waveform of the waveform playlist may bean event waveform (e.g., a waveform that represents a fault,disturbance, or power outage of the power grid). At step 513, the methodcan include measuring the subsequent event waveform with the one or moredevices under test. Measuring can including measuring the electricalcharacteristics of the first event waveform, including but not limitedto measuring current amplitude, phase, voltage amplitude, E-field, etc.Steps 510-513 can be repeated as needed to initiate, deliver, andmeasure all subsequent event waveforms of the waveform playlist.

During all of the method steps described above, an oscilloscope capturecan be performed for comparison and analysis between the waveformsdelivered by the waveform generators and the measurements from the DUTs.The MSUT can be configured process this data for analysis, display, andstorage. This comparison and/or analysis can be used to identify DUTsthat are not operating correctly or are providing measurements outsideof an acceptable error threshold.

In some examples, the phase measurement function of the DUTs can bedisabled, and output data can be collected from the DUTs and MSUT foranalysis against test criteria. System components including testequipment, DUTs, and MSUT can be returned to their quiescent or defaultstates.

The data collected in the method described above may be analyzed fortest validity, qualitative or statistical analysis, and pass/failcriteria. A detailed test report and summary can be generated torepresent these results.

As for additional details pertinent to the present invention, materialsand manufacturing techniques may be employed as within the level ofthose with skill in the relevant art. The same may hold true withrespect to method-based aspects of the invention in terms of additionalacts commonly or logically employed. Also, it is contemplated that anyoptional feature of the inventive variations described may be set forthand claimed independently, or in combination with any one or more of thefeatures described herein. Likewise, reference to a singular item,includes the possibility that there are plural of the same itemspresent. More specifically, as used herein and in the appended claims,the singular forms “a,” “and,” “said,” and “the” include pluralreferents unless the context clearly dictates otherwise. It is furthernoted that the claims may be drafted to exclude any optional element. Assuch, this statement is intended to serve as antecedent basis for use ofsuch exclusive terminology as “solely,” “only” and the like inconnection with the recitation of claim elements, or use of a “negative”limitation. Unless defined otherwise herein, all technical andscientific terms used herein have the same meaning as commonlyunderstood by one of ordinary skill in the art to which this inventionbelongs. The breadth of the present invention is not to be limited bythe subject specification, but rather only by the plain meaning of theclaim terms employed.

What is claimed is:
 1. A power grid simulation system, comprising: aplurality of devices under test configured to measure electricalcharacteristics of a plurality of conductors; a plurality of waveformgenerators, each coupled to a device under test of the plurality ofdevices under test; a multi-phase simulation environment controllercoupled to at least one of the plurality of waveform generators thatinitiates a trigger signal to one or more of the plurality of waveformgenerators to initiate a waveform selected from a waveform playlist;wherein each of the plurality of waveform generators generates thewaveform under a phase lock.
 2. The power grid simulation system ofclaim 1, the multi-phase simulation environment controller being amaster waveform generator of the plurality of waveform generators. 3.The power grid simulation system of claim 1, wherein each of theplurality of waveform generators share a synchronization signal tomaintain the phase lock.
 4. The power grid simulation system of claim 1,the trigger signal being a SCPI command to a master waveform generatorof the plurality of waveform generators.
 5. The power grid simulationsystem of claim 4, further comprising a TTL pulse transmitted from themaster waveform generator to one or more slave waveform generators ofthe plurality of waveform generators, the TTL pulse based on the SCPIcommand.
 6. The power grid simulation system of claim 1, the triggersignal including a GPS derived pulse-per-second signal.
 7. The powergrid simulation system of claim 1, further comprising a GPS distributioninterface remotely located from and operatively coupled to each deviceunder test and configured to transmit GPS signal to each device undertest.
 8. The power grid simulation system of claim 1, wherein eachdevice under test is electrically isolated.
 9. The power grid simulationsystem of claim 1, wherein each device under test is housed inside anRF-isolating metal enclosure.
 10. The power grid simulation system ofclaim 9, power grid simulation system of claim 5, wherein the RFIsolating enclosure is lined with RF absorption material.
 11. The powergrid simulation system of claim 9, wherein the RF isolating enclosurefurther comprises individual control of WAN and GPS access for therespective device under test.
 12. The power grid simulation system ofclaim 9, wherein the RF isolating enclosure further comprises signalpass-throughs for at least one of (a) conductor current, (b) E-fieldsignals, (c) voltage signals, (d) WAN RF, (d) GPS RF, (e) USB, (f)RS-232, and (g) DC power.
 13. The power grid simulation system of claim1, wherein the electrical coupling between a waveform generator and adevice under test further comprises an electronic interface selectedfrom the group of electrical interfaces including: a current amplifier,a current amplifier that drives a Rogowski coil, a voltage amplifier, abalun, a differential amplifier, and a direct test input requiringsimulated Rogowski coil output.
 14. The power grid simulation system ofclaim 1, further comprising one or more oscilloscopes coupled to outputsof each of the plurality of waveform generators to measure outputsignals therefrom.
 15. A power grid simulation method, comprising:receiving, at one or more of a plurality of waveform generators, atrigger signal to initiate a waveform selected from a waveform playlist,each of the plurality of waveform generators coupled to a respectivedevice under test of a plurality of devices under test, each deviceunder test coupled to a separate conductor of a plurality of conductorsof the power grid; generating the waveform while operating under phaselock with others of the plurality of waveform generators.
 16. The powergrid simulation method of claim 15, the receiving including receivingthe trigger signal at a master waveform generator, of the plurality ofwaveform generators, from a multi-phase simulation environmentcontroller.
 17. The power grid simulation method of claim 15, whereineach of the plurality of waveform generators share a synchronizationsignal to maintain the phase lock.
 18. The power grid simulation methodof claim 15, the trigger signal including a SCPI command.
 19. The powergrid simulation method of claim 18, further comprising transmitting aTTL pulse to one or more slave waveform generators of the plurality ofwaveform generators, the TTL pulse based on the SCPI command.
 20. Thepower grid simulation system of claim 1, the trigger signal including aGPS derived pulse-per-second signal.